System and method for supporting tanks

ABSTRACT

A plurality of modular pad units each include a rigid foam core having a polymer coating. Each unit has a similar configuration, substantially uniform thickness and a perimeter shape that includes a circular part, a male key part configured for mating with a female keyway part. The units are arranged by interlocking the units such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit, and the circular parts of the units align to form a circle. The multiple interlocked units providing a circular storage pad that is at least ten feet in diameter and that has a thickness of at least three inches. The bottom of the storage tank is placed directly on the circular storage pad to support and isolate the tank bottom from the ground at the site.

TECHNICAL FIELD

This application relates generally to support of above ground tanks used in the oil and gas industry and other environments and, more particularly, to a system and method that is both lightweight and durable.

BACKGROUND

In the oil and gas production industry, above ground tanks (e.g., commonly referred to as 400 barrel tanks) are used for storage of material (e.g., oil or water). Separating such tanks from the ground is desired. One standard technique for support of such tanks is placement of a metal ring on the ground, which is filled with gravel, with the tank being placed on the gravel bed. However, the system is labor intensive, time consuming and the components are not readily disposable in a landfill. Moreover, tanks sitting on the gravel bed are subject to corrosion and freezing of stored material in extremely cold weather. Another techniques used in the past involved providing segments of blue board coated with a paint, epoxy or urethane coating (similar to sprayed on a truck bed liner) with ratchet straps used to hold 4-5 blue board segments together to form a tank pad. However, the ratchet straps are subject to degradation, and blue board tends to be a weighty product.

It would be desirable to provide a light weight, durable tank support system that is both easy to transport and easy to manipulate and construct on site.

SUMMARY

In one aspect, a method of making a modular pad unit that can be used to produce a circular tank storage pad is provided. The method includes: creating a rigid foam core member having a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part; utilizing a plural component processing system to apply a polymer coating to the rigid foam core member such that the rigid foam core member is encased in the polymer coating produce a modular pad unit; and wherein the resultant modular pad unit has a substantially uniform thickness and perimeter shape with circular part, male key part and female keyway part sized and positioned such that multiple modular pad units can be interconnected in an interlocking manner such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle. The modular pad unit may be sized such that the resulting circles is at least ten feet in diameter (e.g., large enough to hold a large, similar diameter storage tank).

In another aspect, a method of supporting a storage tank in the field involves: utilizing a plurality of modular pad units, each modular pad unit including a rigid foam core having a polymer coating thereon, each modular pad unit having a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part, wherein the male key part is configured for mating with the female keyway part; arranging the modular pad units at a site where the storage tank is to be located, including interlocking the modular pad units such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle, the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and that has a thickness of at least three inches; and placing a bottom of the storage tank directly on the circular storage pad, whereby the circular storage pad supports the storage tank and isolates the storage tank from the ground at the site.

In a further aspect, a supported tank system includes a plurality of modular pad units. Each modular pad unit includes a rigid foam core encased in a polymer coating and has a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part. The male key part of each modular pad unit is configured for mating with the female keyway part of another modular pad unit in a manner that inhibits the male key part from being laterally puller away from the female keyway part. The modular pad units are arranged in an interlocking manner such that the male key part of each modular pad unit mates with the female keyway part of another pad unit and the circular parts of the modular pad units align such that the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and has a thickness of at least three inches. An upright storage tank unit is supported on the circular storage pad. The storage tank has a diameter that is less than or equal to the diameter of the circular storage pad, and a volume of at least 10,000 gallons.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a stacked set of exemplary modular pad units atop a pallet;

FIG. 2 is a perspective view of the modular pad units being spread out;

FIG. 3 is a cross-section of one modular pad unit taken along line 3-3 of FIG. 1;

FIG. 4 is a top plan view showing the perimeter shape of each modular pad unit;

FIG. 5 is a perspective view of the modular pad units separated from each other;

FIG. 6 is a perspective view of the modular pad units interlocked to form a circular tank pad; and

FIG. 7 is a perspective view of a tank supported atop a circular pad formed by modular pad units.

DESCRIPTION

Referring to FIGS. 1-6, one embodiment of a modular pad unit 10 is shown (e.g., four pad units 10A-10D shown in FIGS. 1 and 2). The modular pad unit includes a rigid foam core 12 and a polymer coating 14 that encases the rigid foam core. The rigid foam core 12 may typically have a thickness of at least three inches (e.g., in the range of about three to ten inches). The polymer coating may typically have a thickness of at least 80 mils (e.g., in the range of about 80 to 125 mils).

In one implementation the rigid foam core may be an expanded polystyrene material, though variations are possible. Likewise, in one implementation the polymer coating may be applied using a plural component spray process. For example, a bonded monolithic polymer seal (BMPS) material may be used, made up of a plural component system consisting of an “isocyanate” (also known as a diisocyanate with other variations that may include: isophorone diisocyanate, methylene diphenyl diisocyanate, toluene diisocyanate or hexamethylene diisocyanate) and mixed with one or more of the following: an alcohol, an hydroxyl, a polyol, or an amine, creating a polyurethane or polyurea compound. An example of this material is Custom Linings 911 pure polyurea, available from Custom Linings, Inc. of Beuna Vista, Colo., but there are products that may be used. As used herein, the term plural component processing technique means blending two or more chemicals together in a specific or varying ratio with either direct impingement equipment, equipment utilizing a static mixer assembly to mix/bled the chemicals or by mixing in an open container by hand or by other mechanical mixing method to produce material that cures to some degree. An impingement mix spray process may be best suited to the production of the modular pad units described herein. In one implementation, the polymer coating has a tensile strength of at least 1500 (such as at least 2000 psi or about 2500 to 2700 psi according to ASTM D-412 test), an elongation of at least 200% (according to ASTM D-412 test), a tear strength of at least 300 pli (e.g., 400 pli or greater according to ASTM D-412 test) and a hardness of at least D40 (e.g., D50 or greater according to ASTM D-2240 test).

Each modular pad unit includes a perimeter 14 having a shape that is suited to interlocking of multiple pad units. Specifically, the perimeter 14 includes a circular part 16, a male key part 18 and a female keyway part 20. In the illustrated embodiment, the male key part and female keyway part have complimentary wedge shapes, but other shapes are possible. As seen in FIG. 6, the male key part 18A of a modular pad unit 10A mates with the female keyway part 20A of another modular pad unit 10B such that the male key part 18 and female keyway part 20 are prevented from being laterally pulled (e.g., in the direction of arrow 22) away from each other. Similar interlocks are provided between units 10B and 10C, units 10C and 10D and units 10D and 10A. The circular parts 16A-16D of the modular pad units 10A-10D align to form a circle 24. For the purpose of the tanks and pads contemplated herein, the circle 24 may typically have a diameter that is at least ten feet (e.g., twelve feet or more, as a typical 400 barrel tank used in the oil and gas industry has a diameter in the range of about 12 to 15 feet, and a height in the range of about 12 to 20 feet). In the illustrated embodiment, four modular pad units are interlocked to form a complete pad, but it is recognized that variations are possible (e.g., 2 or 3 modular pad units to form a complete pad or 5 or more modular pad units to form a complete pad). The typical complete pad contains a substantially continuous pad surface that is presented for the purpose of supporting a tank. As shown in the assembled pad, a center opening 40 may be provided, and results from a cutaway corner section 42 of each modular pad unit. The purpose of such cutaways is to facilitate manual laying of the modular pad units during pad assembly (e.g., without trapping or pinching the hand).

Referring to FIG. 7, a tank installation is shown and includes modular pad units 10A-10D interlocked to create a circular storage pad 30. Each modular pad unit includes the rigid foam core encased in a polymer coating as described above, with the male key part of each modular pad unit interlocked with the female keyway part of another modular pad unit and the circular parts (e.g., 16A, 16B etc.) of the modular pad units aligned such that the multiple interlocked modular pad units providing the circular storage pad 30. An upright storage tank unit 32 is supported on the circular storage pad 30. The storage tank 32 has a diameter that is less than or equal to the diameter of the circular storage pad. For example, the diameter of the storage pad 30 may typically be between 1 and 5 inches larger than the diameter of the tank 32, though variations are possible. The storage tank may have a volume of at least 10,000 gallons. For example, a typical 400 barrel storage tank has a volume of roughly 16,800 gallons. The circular storage pad typically has an R-value of at least 26, thereby providing good insulation of the tank 32 from the surrounding ground surface 34. The tank 32 is also elevated from the ground surface 34, which isolates the tank from any water or snow that may collect on the ground surface. In certain implementations, the tank system may be surrounded by a containment wall, which is shown schematically by dashed line form 36.

Thus, a method of supporting a storage tank in the field is provided and involves: utilizing a plurality of modular pad units, each modular pad unit including a rigid foam core having a polymer coating thereon, each modular pad unit having a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part, wherein the male key part is configured for mating with the female keyway part; arranging the modular pad units at a site where the storage tank is to be located, including interlocking the modular pad units such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle, the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and that has a thickness of at least three inches; and placing a bottom of the storage tank directly on the circular storage pad, whereby the circular storage pad supports the storage tank and isolates the storage tank from the ground at the site.

As noted above, the polymer coating may be a polyurethane or polyurea compound that is applied using a plural component spray process, and the polymer coating may have a thickness of at least 80 mils (e.g, between about 80 mils and about 125 mils). The circular storage pad may have an R-value of at least 26 for insulating the tank from the underlying surface on which the pad rests.

For the purpose of ease of transport and handling of the modular pad units, each modular pad unit may have a weight of less than 75 pounds (e.g., less than 50 pounds). Such weights can generally be carried and manipulated by a single individual in the field. In one implementation, each modular pad unit may be sized and shaped for stacking and placement upon a pallet 44 per FIG. 1 (e.g.,. pallet size of 4×5 ft.) for transport.

It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. 

What is claimed is:
 1. A method of supporting a storage tank in the field, the method comprising the steps of: utilizing a plurality of modular pad units, each modular pad unit including a rigid foam core having a polymer coating thereon, each modular pad unit having a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part, wherein the male key part is configured for mating with the female keyway part; arranging the modular pad units at a site where the storage tank is to be located, including interlocking the modular pad units such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle, the multiple interlocked modular pad units providing a circular storage pad that is at least ten feet in diameter and that has a thickness of at least three inches; and placing a bottom of the storage tank directly on the circular storage pad, whereby the circular storage pad supports the storage tank and isolates the storage tank from the ground at the site.
 2. The method of claim 1 wherein the polymer coating is a polyurethane or polyurea compound that is applied using a plural component spray process.
 3. The method of claim 1 wherein the polymer coating has a thickness of at least 80 mils.
 4. The method of claim 3 wherein the polymer coating has a thickness of between about 80 mils and about 125 mils.
 5. The method of claim 1 wherein the circular storage pad has an R-value of at least
 26. 6. The method of claim 1 wherein at least three modular pad units are interlocked to form the circular storage pad.
 7. The method of claim 6 wherein at least four modular pad units are interlocked to form the circular storage pad.
 8. The method of claim 1 wherein a weight of each modular pad unit is less than 75 pounds.
 9. The method of claim 8 wherein a weight of each modular pad unit is less than 50 pounds.
 10. The method of claim 1 wherein the polymer coating has a tensile strength of at least 1500, an elongation of at least 200%, a tear strength of at least 300 pli and a hardness of at least D40.
 11. A supported tank system, comprising: a plurality of modular pad units, each modular pad unit including a rigid foam core encased in a polymer coating, each modular pad unit having a similar configuration with a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part, wherein the male key part of each modular pad unit is configured for mating with the female keyway part of another modular pad unit in a manner that inhibits the male key part from being laterally puller away from the female keyway part; the modular pad units arranged in an interlocking manner such that the male key part of each modular pad unit mates with the female keyway part of another pad unit and the circular parts of the modular pad units align such that the multiple interlocked modular pad units providing a strapless circular storage pad that is at least ten feet in diameter and has a thickness of at least three inches; and an upright storage tank unit supported on the circular storage pad, the storage tank having a diameter that is less than or equal to the diameter of the circular storage pad, the storage tank having a volume of at least 10,000 gallons.
 12. The system of claim 11, wherein the polymer coating is one of a polyurethane or polyurea compound that is applied using a plural component spray process.
 13. The system of claim 11 wherein the polymer coating has a thickness of at least 80 mils.
 14. The system of claim 11 wherein the circular storage pad has an R-value of at least
 26. 15. The system of claim 11 wherein at least three modular pad units are interlocked to form the circular storage pad.
 16. The system of claim 15 wherein at least four modular pad units are interlocked to form the circular storage pad.
 17. The system of claim 11 wherein a weight of each modular pad unit is less than 75 pounds.
 18. The system of claim 11 wherein the rigid foam core is formed by a expanded polystyrene material.
 19. The system of claim 11 wherein the polymer coating has a tensile strength of at least 1500, an elongation of at least 200%, a tear strength of at least 300 pli and a hardness of at least D40.
 20. A method of making a modular pad unit that can be used to produce a circular tank storage pad, the method comprising the steps of: creating a rigid foam core member having a substantially uniform thickness and a perimeter shape that includes a circular part, a male key part and a female keyway part; utilizing a plural component processing system to apply a polymer coating to the rigid foam core member such that the rigid foam core member is encased in the polymer coating produce a modular pad unit; wherein the resultant modular pad unit has a substantially uniform thickness and perimeter shape with circular part, male key part and female keyway part sized and positioned such that multiple modular pad units can be interconnected in an interlocking manner such that the male key part of each modular pad unit mates with the female keyway part of another modular pad unit and the circular parts of the modular pad units align to form a circle that is at least ten feet in diameter.
 21. The method of claim 20 wherein the polymer coating is polyurethane or polyurea compound.
 22. The method of claim 20 wherein the polymer coating is applied to provide a resulting thickness of at least 80 mils.
 23. The method of claim 20 wherein a weight of the modular pad unit is less than 75 pounds.
 24. The method of claim 20 wherein a weight of the modular pad unit is less than 50 pounds.
 25. The method of claim 1 wherein the polymer coating has a tensile strength of at least 1500, an elongation of at least 200%, a tear strength of at least 300 pli and a hardness of at least D40. 